The company I work for is using SharePoint as a CMS for it's public facing website. I recently enabled FBA (Forms Based Authentication) for the site in order to provide some user specific functionality, but this has caused a side effect with Word / Excel files when opened from the site using Office 2007 / 2010.

Some users are challenged for authentication when opening a Word / Excel document from IE (but not when they select "save file" instead of "open file"). A window pops up behind IE / Word / Excel (so you often don't realise it's there) showing the sites login page. If the window is dismissed then the document continues to open normally.

It seems to be environmental. Most Office 2007 / 2010 users internally experience this and we've had confirmed reports externally of this happening.

Anyone know how to prevent this behaviour?

In case it's relevant: The company also has an internal SharePoint site using NTML authentication allowing internal users to edit the same content visible externally. So there are 2 sharepoint sites being driven from the same content:

http://www.domain.com - Site visible to external users. Uses FBA to allow users access to a few special pages.

I originally suspected the SharePoint header added to responses may be alerting Office to check for authentication to allow extended functionality, but I remove the response header in IIS and it didn't make any difference.

The Authentication Provider for the FBA enabled site has "Enable Client Integration" set to "No". I've tried both the "yes" and "No" options but neither makes any difference.

Gavin, Have you found a permanent solution to this? I am also experiencing the same issue. We only run SP2007 as an internal portal with auto-authentication happening via AD accounts. When staff try to open a Word or Excel file they get the prompt for credentials. Regardless of what they enter it will never be accepted as valid but if they just cancel out of the prompt the documents open fine. Hope that you can share your success with me. Thanks SS
–
user3769Jun 16 '11 at 19:50

Hmmm... I'm not getting links to reply to comments (or "add comment") for some reason so comment replies here: @djeeg - Clients are a mix of Windows versions - XP, Vista and Windows 7. @Sandra - Sorry, not found a solution to this issue yet myself. Please share if you find one. Cheers.
–
GavinJun 20 '11 at 20:49

1

Welcome to SharePoint.SE! You should modify your original question to add additional information. Regarding commenting, looks like you had two accounts so I went ahead and merged them. You should be able to leave comments for your question. Additionally, once you gain 50 reputation you'll be able to leave a comment anywhere.
–
Kit MenkeJun 20 '11 at 21:50